Contrail Shadows and so on

[susier]

Hi all.


We stopped the car today amid much consternation in the back seat, when my boys noticed a very intriguing sight.


We were driving over some very flat terrain and there was a lot of sky...a good few planes heading east south east around a 103 track, as they do round here, and one of them had ahead of it a straight, dark grey trail, right down to the horizon, as if it were a continuation of the white trail behind the plane.


We stared for a while, I sought my camera phone in my bag, but the battery was flat, so we continued on our way.


Anyhow I just looked it up and came across an explanation here:


Contrails, Dark Lines, Black Beams, & "Chemtrails" - Contrail Science » Contrail Science (http://contrailscience.com/contrails-dark-lines-chemtrails/)


As an aside it was quite amusing to read the comments, as no one in their right mind would ever want to bother chemically altering this part of the world. Everyone is already a bit weird here....the place was written off long ago : )


So it wasn't a chemtrail anyway. But how did I get to my age without ever seeing one before?


(ETA: I don't mean the UK in general...just this corner of it...!)

[HEATHROW DIRECTOR]

Don't worry; they're not uncommon.

[Capetonian]

Some of the comments are hilarious, but here's a sensible one :

p.s. if chemtrails targeted stupid people, i am for the genocide.

[DaveReidUK]

one of them had ahead of it a straight, dark grey trail, right down to the horizon, as if it were a continuation of the white trail behind the plane.There no technology that's capable of producing a contrail ahead of an aircraft.

Having said that, I think you've answered your own question:

a good few planes heading east south east around a 103 track, as they do round hereLikely a persisting contrail from a preceding aircraft.

[WIDN62]

You don't say what time of day it was! However, sun in the west, aircraft heading east producing contrail. If the aircraft was flying over a thin layer of cirrus cloud, you would see the shadow of the contrail on the cloud as a grey line. They are commonly seen from inside the aircraft, but not so obvious from the ground as the cirrus has to be thin enough for the ground observer to see through it. I saw one a couple of days ago.

[susier]

Sorry, and thank you for the replies - it was around 10am. We're in Kent so stuff goes over climbing through around 200 out of LHR or passing over from the USA to France/Germany mostly at maybe 370/390. This was a high one.


Sun was up and very bright but I'm not sure how it configured.


And yes, it wasn't a trail, but it looked just like one - like in some of those photos in the link, but slightly more of a sharp image, then fading out like a rainbow does towards the ground. All in a perfect line with the existing contrail, but ahead of the plane, which was heading away from us therefore looked like on a vertical line and barely perceptible to be moving.


My eldest son is 11 and thought it 'looked like fuel falling'...he has an active imagination : )


The grey line disappeared after a few more minutes driving. There were plenty other trails in a similar direction, I wondered about it following another plane but I think the link explains it as a shadow.


I never noticed one because I think I just never looked before, iyswim? They are fascinating things these planes.

[joy ride]

I started noticing shadows of contrails a few years back, sometimes they are parallel and sometimes they are in-line ahead so it look like the plane is following a road; I have also seen low clouds casting a shadow on thin higher cloud. When the sun is below the cloud or vapour trail their shadow is projected upwards. Sun, atmosphere and weather produce some wonderful sights.

[susier]

Yes, that's exactly what it was like - as if it were following its own personal road!


When life gets too much all I have to do is look up...it brings a perspective that can be elusive on the ground.

[joy ride]

I use the A2 fairly regularly between London and the Medway towns and there seem to be a slightly higher than normal amount of unusual weather/atmosphere conditions, possibly because of the landscape and two close rivers. I have seen these trail shadows quite often there and it is where I also first saw sunbows.

A rainbow seen from a high van at the highest point of M25 Dordfart, er, Dartford Bridge is a fine sight.

[Noah Zark.]

Another way to think of it is to look at the black line from the ground upwards, to where it reaches the contrail, and project the line further up until you reach the sun, then it is obviously a shadow.

[Old Photo.Fanatic]

Here is an example of contrail shadow.
I took this Photo. at Brussels in May 2008.

http://i611.photobucket.com/albums/tt200/phredd10/Miscellanious/DSC_0103_zps558a7a43.jpg

OPF